Effects of perennial Legume-Gramineae mixtures on forage yield and quality in the Hexi Corridor Region

In order to study the production performance of Legume – Gramineae artificial grassland, we assessed five different patterns of mixed sowing with Medicago sativa, Onobrychis viciifolia, Bromus inermis, and Elytrigia elongata. The results indicated that the Legume – Gramineae mixtures contributed to a significant increase in forage yield, among which, that of the “M. sativa + B. inermis + E. elongata” mixture was the highest. Compared with the other mixed and unicast sowings, this mixture increased yield by 4.2%～92.5%, 7.5%～134.9%, and 11.6%～313.6% in the first, second, and third years, respectively. The land equivalent ratio of all mixed sowing combinations was greater than 1, among which, the ratio obtained for the “M. sativa + B. inermis + E. elongata” mixture was the highest. The stability of this combination gradually increased with an increase in the time post-sowing and tended to become stable. The Legume – Gramineae mixtures were found to contribute to increases in the contents of crude protein, crude fat, crude ash, and semi-fiber, as well as the yield of digestible nutrients per unit area, with the quality of the “M. sativa + B. inermis + E. elongata” combination being found to be the best among all mixed sowing combinations. To comprehensively evaluate the indices of yield and quality of each treatment, we evaluated order preference by similarity to an ideal solution model, which revealed that the “M. sativa + B. inermis + E. elongata” combination has the highest degree of fit with the ideal mixed sowing combination. This mixture is thus considered suitable for planting in the desert oasis area of the Hexi Corridor Region and should accordingly be promoted.